So, the presented model results in a nonexponential decay of the initial coherent CSFE ensemble (REF ). The time dependence of the decay (REF ) is parameterized by time \({\cal T}\)  (Fig. 2.). The number of zero magnetoexcitons decreases by half during time \({\cal T}\!/n(0)\)  inversely proportional to the initial CSFE concentration. A tenfold decrease will take time \(\approx \!10{\cal T}\!/n(0)\) , therefore, for \(n(0)\!\leqslant \!0.01\)  it occurs during \(\gtrsim \!1\,\mu \) s [cf. the 3D characteristic electron-phonon scattering time \(\tau _A\)  (REF ) which is \(\sim \!0.1\,\) ps if \(q\!\sim \!k_z\!\sim 1\) , and the CSFE lifetime which is \(>\!50\,\mu \) s at \(B\!=\!4.18\,\) T if estimated on the basis of the recent experimental data\(\,\)[1]}).
